6 site survey – Nortel Networks DCT1900 User Manual

Page 117

Technical Product Manual - DCT1900

Configuration Directions, Base Station Planning

Config-DCT1900/R8/mw

3-3

3.6

Site Survey

To satisfy area coverage and traffic demands, the site must be surveyed in order to determine the
number and position of Base Stations. To do a site survey, a site survey tool and floor plans of the
building are required. With the help of these tools proper Base Station planning can be done.
Samples must be taken to determine an average cell size. With the average cell size, Base Station
positions can be indicated on the map together with the area covered by each Base Station.
Difficult spots can be mapped as well. After this, the planned positions can be verified with the site
survey tool and with the help of the traffic requirements, a final plan can be made.

When doing the survey with the Site Survey Tool, read the instructions below:

Observe the building to find a "typical area"

Modern buildings usually have standard constructions. In older buildings, due to renovations
or expansions, areas with different structures may exist. However, inside these areas a
uniformity in structure can be found again.

Find an area with a typical structure for the building and of about the expected cell size. This
area will be used to determine the typical cell size. With a building with different structures, find
the cell size of each of those areas, so that differences in "typical cell size" can be detected.

Measure the horizontal cell size on the middle floor, see Figure 3–2, (1)

The cell size is measured by setting up a call with a portable and listening to the speech
quality. This test is more accurate, faster and easier to use than the RQI indicator of the
Portable Telephone’s DCS. See Section 6, "Commissioning" in this manual.

The cell size can be determined as follows:
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Install a Base Station in the middle of the "typical area" and power the Site Survey Tool.

Switch a Portable Telephone to DCA mode and set up a call.

Walk away from the Base Station in one direction. Also enter rooms with the Portable

Telephone switching to your left and right hand.

The edge of the cell is found as soon as crackling sounds and/or mutes appear. Step back

to where no mutes or sounds were heard. Verify whether the RQI remains stable on 20

and measure the distance to the Base Station. Within a cell, no mutes or clicks should be

heard and the RQI should be stable on value 20.

Do the same in the opposite direction.

The two distances should be about the same. This is the horizontal coverage on the floor

of the Base Station.

Measure horizontal range on floor above, see Figure 3–2, (2)

Go to the floor above, leaving the Base Station on its current location and measure the
horizontal coverage here.